Large area electronic energy control, display or lighting products that are permanently mounted in structures, such as buildings, ships, aircraft, trains, buses, or cars, may include electronic or electro-optical devices (collectively “electronic energy control devices”), such as electrochromic, OLED, electroluminescent, electro-reflective, LCD, and other monolithic display or lighting devices, in which an electronically and optically active media is contained between closely spaced electrodes. The appearance of the lighting or a display created by such electronic energy control devices may be adversely affected by the presence of defects in the active or inactive media that locally modify the potential between the electrodes.
Electronic energy control devices by also be used to modify light transmission over small areas, for example, displays, illuminators, vision systems, sensors, and similar devices. The undesirable effect of a defect is even greater when the size of the device becomes similar to, or even smaller, that the area affected by the defect.
For example, electrochromic devices include electrochromic materials that are known to change their optical properties, in response to application of an electrical potential, so as to make the device, for example, more or less transparent or reflective, or have a desired coloration.
The manufacture of an electrochromic device typically includes forming an electrochromic (EC) film stack including a plurality of layers of conductive and electrochromic material on a substrate, such as glass. See, for example, U.S. Pat. Nos. 5,321,544, 6,856,444, 7,372,610 and 7,593,154, incorporated by reference herein. During the manufacturing process, defects sometimes may be formed in one or more of the layers of the EC film that can cause the electrochromic device to have a different optical behavior than desired, or lack a desired optical behavior, at or near the location of the defect when the device is operated by applying an electrical potential thereto. The defect may be a short between conductive layers of the EC film stack caused, for example, by foreign contaminants, or a material non-uniformity or scratch in one or more of layers of the EC film stack, that causes the EC device, when operated, to have at the location of the defect optical properties different than those desired and present at locations adjacent to the defect. The defect, hence, may cause the EC device to have an undesirable aesthetic appearance when operated.
Although various techniques are known and may be performed to repair a defect in an electronic energy control device, such as an electrochromic device, during manufacture, some defects still may remain in a final, manufactured electronic energy control device product. For example, an electrochromic device included in a final, manufactured electrochromic device product, such as an insulated glass unit (IGU), may include defects visible only when the electrochromic device transitions between an energized and non-energized state, and defects not visible in visible or near infrared light. Oftentimes, such defects are noticed or appear only after installation of the electrochromic device product, for example, as an exterior window in a high rise building. It is always more desirable to eliminate the cause of a defect than to try to repair a defect after it has occurred.
It is desirable to reduce the total number of defects or, if possible, completely eliminate all visual or non-visual defects. During the manufacturing of an EC device, or related devices, particulate material or other contaminants may be introduced. For example, the vacuum process for the deposition of the film stack in electrochromic devices may be interrupted at some point in between the deposition of the upper and lower electrical conductors for the purpose of patterning the lower conductor into the proper electrical circuit. After patterning the lower conductor (so that the appropriate electrical connections can be made and voltage applied), EC device processing continues by deposition of the remainder of the film stack. Particles may be generated by the removal, patterning, and other steps between the two deposition steps can have visible defects in the completed EC device, including, as noted above, those defects which may become visible to the operator.
Conventional application of water to remove particulate contaminants may, in some instances, leave water spots, stains, or water flow patterns. Depending on the nature of the substrate or surface being exposed to the water treatment or cleaning, the substrate may bleach, discolor, or become less electrically efficient. In a worst case scenario, water could lead to uniformity differences in coloration of EC devices. Such water-induced defects may only appear during dynamic switching of an electrochromic device, making them difficult to detect, yet sill unappealing to users of the device. There remains the need to remove particulate material or other contaminants generated during the manufacturing process without degrading any of the material surfaces or film stacks present in an EC device or other like device (EC device, photochromic device, thermochromic device, liquid crystal display, organic light emitting diode, batteries, or individual thin film materials in other discrete or stand-alone applications).